Cooking

Canning Pressure Calculator

Calculate pressure canning processing times adjusted for your altitude, jar size, and food type.

Quick Answer

At sea level, most vegetables process at 10 PSI. Above 1,000 feet, increase to 15 PSI for weighted-gauge canners. Processing times vary by food type and jar size — green beans take 25 minutes in quarts, while meat takes 75-90 minutes.

⚠ Safety Notice

Always follow USDA and NCHFP guidelines for pressure canning. This tool provides general guidance. Consult your canner manufacturer’s instructions and tested recipes for specific food items.

Canning Settings

Results

25 min

Processing Time

10 PSI

Pressure (weighted gauge)

About This Tool

The Canning Pressure Calculator determines the correct processing time and pressure for pressure canning based on your altitude, jar size, food type, and canner type. Pressure canning is the only safe method for preserving low-acid foods at home, including vegetables, meats, poultry, and seafood. The temperatures reached inside a pressure canner (240-250 degrees Fahrenheit) are necessary to destroy Clostridium botulinum spores, which cause botulism.

Why Altitude Matters

Water boils at lower temperatures as altitude increases. At sea level, water boils at 212 degrees Fahrenheit. At 5,000 feet, it boils at about 203 degrees. Since the internal temperature of the canner must reach at least 240 degrees to safely process low-acid foods, you need more pressure at higher altitudes to compensate. For weighted-gauge canners, this means switching from 10 PSI to 15 PSI above 1,000 feet. Dial-gauge canners allow more precise adjustments in 1-2 PSI increments.

Weighted vs. Dial Gauge Canners

Weighted-gauge canners use a weighted regulator that jiggles or rocks to maintain pressure. They are simpler and do not require calibration, but only operate at fixed pressure settings (5, 10, or 15 PSI). Dial-gauge canners have a numbered pressure dial that allows you to set specific pressures. The dial must be tested for accuracy annually, as an inaccurate gauge can lead to under-processing. Both types are effective when used correctly according to manufacturer instructions.

Processing Time Guidelines

Processing times are determined by extensive testing conducted by the USDA and university extension services. Times account for the density of the food, how heat penetrates through the jar, and the time needed for the center of the jar to reach the target temperature. Never reduce processing times. You may safely process for longer than recommended, but shorter times risk unsafe food. The times in this calculator are based on USDA Complete Guide to Home Canning recommendations.

Frequently Asked Questions

Can I use a water bath canner for vegetables?
No. Low-acid foods like vegetables, meats, and poultry must be processed in a pressure canner. Water bath canning only reaches 212 degrees Fahrenheit, which is not hot enough to destroy botulism spores. Only high-acid foods like fruits, pickles, and acidified tomatoes can be safely water-bath canned.
What happens if I lose pressure during processing?
If pressure drops below the required level during processing, you must bring the pressure back up and restart the processing time from the beginning. Partial processing does not count toward the required time because the internal temperature of the food dropped below the safe zone.
How do I find my altitude?
You can search your city and altitude online or use a GPS-enabled phone. Many weather apps also show elevation. Your local county extension office can tell you the altitude for your area. Even rough estimates are fine since pressure adjustments use broad altitude ranges.
Can I double-stack jars in a pressure canner?
Yes, if your canner is tall enough. Place a second rack between layers. Processing times do not change for double-stacked jars in a pressure canner because the steam circulates around all jars equally. Make sure steam can flow freely between jars.
Why are processing times different for pints and quarts?
Quart jars contain more food, so heat takes longer to penetrate to the center of the jar. The center must reach the target temperature and stay there long enough to destroy harmful organisms. Pint jars heat through faster due to their smaller volume.